If it has a PCI-e slot then yes, you can just put it in, but just remember the 8800 GT isn't a modern card so it probably won't perform that well in modern games, but if you're gonna do like Minecraft & Counter Strike you're good.
Thanks. No gaming. Just photos, home videos etc. I've getting lines and will only run on low res. just don't want to chuck the thing. Will it take any replacement video card? It does have a pic-e slot. I took it apart and cleaned it. It ran fine for about one hour, then same thing